1. Field of the Invention
The present invention relates to pneumatic tires.
2. Description of the Related Art
As long as automotive vehicles have had inflatable tires, vehicle operators have had to monitor the pressure of the tires. Over time, there have been a number of methods to do this, including the use of tire gauges and the like. However, the tire gauge often becomes lost, making tire pressure measurement impossible without it. Other techniques rely on the general configuration of the tire to make a guess at whether it is properly inflated. However, this takes a considerable about of skill and is beyond the reach of most amateur vehicle operators.
A number of recent developments have proposed the use of electronic detectors and the like to present an audible or visible signal either in the cab of the vehicle or on the face of the tire to indicate when the tire has become incorrectly inflated. However, these are relatively complicated and will be unsuitable for those vehicles or owners who are disinclined to purchase them.
It is another object of the present invention to provide a novel technique for detecting tire inflation by using the properties of the profile of the tire as the tire changes inflation.
A pneumatic vehicle tire has a pair of sidewalls and a ground engaging surface extending therebetween, at least one of the sidewalls bearing an outwardly visible inflation-indicating ring and a pair of sighting rings. At least a first portion of the inflation-indicating ring is positioned relative to the ground engaging surface wherein, when the tire becomes incorrectly under-inflated, the first portion changes from one position to another visibly distinct position when viewed along a sight line indicated by a pre-determined relationship between the pair of sighting rings.
Accordingly, the present invention provides a pneumatic vehicle tire comprising a pair of sidewalls and a ground engaging surface extending therebetween, at least one of said sidewalls bearing an outwardly visible inflation indicator ring and a pair of second rings, at least a first portion of said inflation indicator ring being positioned relative to said ground engaging surface such that when the tire becomes incorrectly inflated, said first portion is arranged to change from one position to another visibly distinct position when viewed from a viewing position whereat one ring of said pair of second rings has a pre-determined position relative to another ring of said pair of second rings. For example, the proper sight line may be reached when one of the pair of sight rings is at least partially, or just barely, concealed by, or is immediately beside, the other of the pair of sight rings.
In still another aspect of the present invention, there is provided a technique for monitoring pressure in a tire, comprising: providing a tire with an outwardly visible inflation-indicating ring and a pair of sighting rings on a sidewall arranged such that at least a portion of said inflation-indicating ring changes from one position to another visibly distinct position when viewed from a sight line determined by a pre-determined relative position of said pair of sighting rings when the tire becomes incorrectly inflated.
In another aspect of this invention, there is provided a tire having three ring formations on its sidewall. The first and second ring formations provide a register to guide the viewing of the third outer ring formation. The user may align the first innermost and the second middle rings in order to position his line of sight at the correct elevation and distance from the tire. It is in this position that he can correctly view the third formation in order to determine the condition of the tire.
In one embodiment, the tire has three rings wherein a portion of the outer ring closest to the road becomes concealed when viewed from a position located such that the middle ring closest to the road is just barely concealed by the inner ring when the tire is incorrectly inflated.
In another embodiment, the tire has at least three rings including an outer ring and a pair of central ring formations, wherein a portion of the outer ring closest to the road becomes concealed when viewed from a position located such that the central ring closest to the road is just barely concealed by the inner central ring when the tire is incorrectly inflated.
In one embodiment, the portion of the inflation-indicating ring is concealed when the tire becomes incorrectly under-inflated. In another embodiment, the portion of the inflation-indicating ring is revealed when the tire becomes incorrectly over-inflated.
In another embodiment, the first portion is located on said sidewall and sufficiently close to said ground engaging surface to be concealed by an overlapping portion of the sidewall when the tire is moderately under-inflated.
In another of its aspects, the present invention provides an automobile comprising a plurality of pneumatic tires as defined herein above.
Other features and advantages of the invention will become apparent to one of ordinary skill in the art upon a review of the following drawings in conjunction with the following description of example embodiments of the invention.